This invention relates to a method for the continuous preparation of organopolysiloxane emulsions. More particularly, this invention relates to a highly productive method for the preparation of uniform and highly dispersed organopolysiloxane emulsions.
Organopolysiloxane emulsions are widely used in industry as lubricants, release agents, fiber-treatment agents, glass fiber-treatment agents, cosmetic bases, lustrants and paint additives.
Methods already known for the preparation of organopolysiloxane emulsions are exemplified by (a) mixing the starting liquid organopolysiloxane, emulsifying agent and water using a mixer that applies a stirring action, for example, a Henschel mixer or kneader mixer and (b) mixing said starting materials through the application of a shearing action using a colloid mill. In addition, Japanese Patent Publication Number Sho 59-51565 [51,565/1984] teaches a method that uses a cylindrical container having therein, a stirring element comprising at least 3 disks installed at a fixed interval on a rotating axle. Diorganopolysiloxane oil, emulsifying agent and water are continuously fed in this method to the cylindrical container and are sheared and stirred by this stirring element.
However, each of these prior-art methods is poorly adaptable to the continuous mass production of uniform, highly dispersed organopolysiloxane emulsions, and each suffers from the problem of poor productivity. In the particular case of the method disclosed in Japanese Patent Publication Number Sho 59-51565, shearing and stirring must be conducted with the application of pressure in order to make a uniform emulsion, and this automatically incurs such disadvantages as increased operating costs due to the increased drive energy as well as costs associated with reinforcing the equipment structure.